Anakin could encounter future versions of his friends or enemies from the past. For instance, he could run into a future version of Obi - Wan Kenobi who has also somehow traveled to that future time. Or perhaps he meets a new generation of Sith who have different motives and methods compared to the Sith he knew in his own time. They could challenge his understanding of the dark side and the Force in general.
There is a possibility that he meets some sort of time - traveling guardians in the future. These could be beings whose sole purpose is to protect the timeline. They might initially view Anakin as a threat since his unexpected arrival could disrupt the future. Anakin would then have to convince them that he means no harm and that he is just as lost in this new time as they might think he is.
There could be a hermit or an outcast Jedi or Sith on Dathomir. Anakin meeting this character could lead to a great revelation. Maybe this character has been in hiding on Dathomir for years, observing the balance of the Force there, and Anakin's arrival disrupts that balance and forces an interaction that changes Anakin's perspective on many things.
Obviously, he would interact with his younger self. He could try to guide his younger self, offer advice on how to control the Force better and how to deal with the temptations of the Dark Side.
Maybe Anakin would be shocked by the advanced technology in the future. He might see flying cars and towering skyscrapers everywhere.
He could meet his future self. This would be a very interesting encounter as he could learn from his future self about what he has accomplished and what mistakes he should avoid. He might also meet the future generations of his family, like his grandchildren or great - grandchildren.
There's a chance he could meet an older and wiser Kakashi. Kakashi might have new insights and stories to share with Naruto from all the years that have passed. And also, he could run into future shinobi who look up to him as a legend from the past.
In a fanfic, Sith Lords are likely candidates to kidnap Anakin. They might see him as a valuable asset or a threat to their plans and decide to take him captive. For example, Darth Maul could try to kidnap Anakin to get revenge on the Jedi or to use him in some dark scheme.
Percy might meet an old enemy who has somehow been resurrected or changed in the future. This enemy could be more powerful and have a new plan to take over the world or destroy the demigods. Or he could meet a group of time - traveling demigods from an even further future who are trying to fix something in Percy's future that has gone wrong.
He could meet the descendants of his friends, like the grandchildren of Ron and Hermione. They might show him around the future wizarding world and tell him about all the changes that have occurred. Also, he may run into some new and powerful wizards who have emerged in the future and learn from them about new magical techniques.
One idea could be that Anakin travels to a future where the Jedi Order has been rebuilt in a new and unexpected way. He might initially be confused by the different teachings and practices. For example, the new Jedi might have a more inclusive approach, accepting Force - users from all walks of life, not just those trained from a young age as in his time. This could lead to Anakin having to re - evaluate his own understanding of the Force and his place in the Jedi legacy.
Obviously, the members of the Jedi council would be main characters. Yoda, for instance, would play a crucial role. His wisdom and experience would lead him to question Anakin's motives and the truthfulness of what he says.